The importance of micronutrients in animal diets is well documented. Piglets usually suffer from iron deficiency, and various methods of administering supplemental iron have been described, including oral feeding (U.S. Pat. Nos. 3,491,187 and 4,067,994); parenteral administration (injection) or slow release tablets (U.S. Pat. Nos. 3,952,036 and 3,975,513).
A substantial amount of information has been published documenting various forms of iron employed to treat anemia in newborn piglets:
______________________________________ Author(s) Title Reference ______________________________________ Ackerman, et al Transmissible Gastroenter- Am. J. Vet. itis in Three-Week-Old Res., Vol. 33, Pigs: Study of Anemia No. 1 (January and Iron Absorption 1972) Furugouri, K. Plasma Iron and Total J. of Animal Iron-Binding Capacity Science, Vol. in Piglets in Anemia and 34, No. 3, 1972 Iron Administration Danielson, et al Supplemental Iron for the J. of Animal Artificially Reared Science, Vol. Piglet 40, No. 4, 1975 Thoren-Tolling Cellular Distribution of Can. J. Comp. et al Orally and Intramuscu- Med., Volume larly Administered Iron 41, 1977 Dextran in Newborn Piglets Webster, et al Evaluation of Oral Iron Australian Vet. Galactan as a Method J., Volume 54, of Iron Supplementation 1978 for Intensively Housed Suckling Piglets Brady, et al Evaluation of an Amino J. of Animal Acid-Iron Chelate Science, Volume Hematinic for the 47, No. 5, 1978 Baby Pig ______________________________________
In the past, iron has been administered to piglets primarily as an oral feed or by parenteral injection. In the case of injections, it has been necessary to repeat the procedure more than once during the growing period of the piglets, with resultant stress, plus extra handling, which adds to the cost of meat production. Administration as an oral feed is inherently uncertain. Some piglets may receive excess iron while others in the litter may not receive enough to prevent iron deficiency anemia.
It has been reported in the literature that anemia can also occur in rapidly growing lambs under intensive systems of management. Iron-dextran injections were used to combat the problem. See: Notes, Canadian Journal of Animal Science 59:809-811, December 1979. Subcutaneous implanting of iron dextran in lambs was not suggested.
SEA's Livestock Insects Laboratories (USDA) in Beltsville, Md., and Kerrville, Tex., have reported that grubs emerging from infested calves can be controlled by the use of ear-implanted pellets which release minute amounts of experimental compounds. Compounds are reported to be under development which will be effective against bloodsucking insects and ticks in very low dose levels in an animal's blood stream. See: Animal Nutrition and Health/January-February 1980, "Abstracts", page 10.
Selenium (Se) is added to many poultry feeds, turkey feed in particular, to avoid selenium deficiency diseases. The addition of selenium to feeds for swine, sheep, cattle and chickens (0.1 ppm) and for turkeys (0.2 ppm) has been approved by FDA (21 CFR 573.920; Federal Register 44(9):5342, 1979. Implanting of poultry to supply micronutrients in a slow-release mode has not been suggested until now, however.
Selenium deficiency has been reported to be associated with nutritional muscular dystrophy (white-muscle disease, WMD) in lambs, calves and foals, and other diseases in poultry and swine. See: Johnson, C. M., "Selenium in the Environment", Residue Reviews 62:102(1976); Cunha, T. J., "The Value of Feeding Selenium", Feedstuffs, May 21, 1973, page 48. At present, the only known commercial treatment for selenium deficient young lambs is subcutaneous or intramuscular injection of an oil-based, sodium selenite-containing compound.
Yound calves have been treated with micronutrients including iron, zinc, manganese and selenium. Treating veal calves with injections of iron dextran is described in: Mollerberg et al, 1975, Acta Vet. Scand. 16:197, cited by Church, D. C. et al 1979, Digestive Physiology and Nutrition of Ruminants, Volume 2, O&B Books, Inc. Corvallis, Oreg., page 130.